af1812090b
The raid6 code matches kernel implementation that also does the unaligned access. So to keep the code close, add helpers for unaligned native access and use them. The helpers are local as we don't plan to use them elsewhere. Reported-by: Anatoly Pugachev <matorola@gmail.com> Signed-off-by: David Sterba <dsterba@suse.com>
110 lines
2.8 KiB
C
110 lines
2.8 KiB
C
/* -*- linux-c -*- ------------------------------------------------------- *
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*
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* Copyright 2002-2004 H. Peter Anvin - All Rights Reserved
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, Inc., 53 Temple Place Ste 330,
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* Boston MA 02111-1307, USA; either version 2 of the License, or
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* (at your option) any later version; incorporated herein by reference.
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*
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* ----------------------------------------------------------------------- */
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/*
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* Added helpers for unaligned native int access
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*/
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/*
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* raid6int1.c
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*
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* 1-way unrolled portable integer math RAID-6 instruction set
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*
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* This file was postprocessed using unroll.pl and then ported to userspace
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*/
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#include <stdint.h>
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#include <unistd.h>
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#include "kerncompat.h"
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#include "ctree.h"
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#include "disk-io.h"
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/*
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* This is the C data type to use
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*/
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/* Change this from BITS_PER_LONG if there is something better... */
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#if BITS_PER_LONG == 64
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# define NBYTES(x) ((x) * 0x0101010101010101UL)
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# define NSIZE 8
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# define NSHIFT 3
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typedef uint64_t unative_t;
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#define put_unaligned_native(val,p) put_unaligned_64((val),(p))
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#define get_unaligned_native(p) get_unaligned_64((p))
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#else
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# define NBYTES(x) ((x) * 0x01010101U)
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# define NSIZE 4
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# define NSHIFT 2
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typedef uint32_t unative_t;
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#define put_unaligned_native(val,p) put_unaligned_32((val),(p))
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#define get_unaligned_native(p) get_unaligned_32((p))
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#endif
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/*
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* These sub-operations are separate inlines since they can sometimes be
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* specially optimized using architecture-specific hacks.
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*/
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/*
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* The SHLBYTE() operation shifts each byte left by 1, *not*
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* rolling over into the next byte
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*/
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static inline __attribute_const__ unative_t SHLBYTE(unative_t v)
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{
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unative_t vv;
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vv = (v << 1) & NBYTES(0xfe);
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return vv;
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}
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/*
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* The MASK() operation returns 0xFF in any byte for which the high
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* bit is 1, 0x00 for any byte for which the high bit is 0.
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*/
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static inline __attribute_const__ unative_t MASK(unative_t v)
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{
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unative_t vv;
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vv = v & NBYTES(0x80);
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vv = (vv << 1) - (vv >> 7); /* Overflow on the top bit is OK */
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return vv;
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}
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void raid6_gen_syndrome(int disks, size_t bytes, void **ptrs)
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{
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uint8_t **dptr = (uint8_t **)ptrs;
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uint8_t *p, *q;
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int d, z, z0;
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unative_t wd0, wq0, wp0, w10, w20;
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z0 = disks - 3; /* Highest data disk */
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p = dptr[z0+1]; /* XOR parity */
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q = dptr[z0+2]; /* RS syndrome */
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for ( d = 0 ; d < bytes ; d += NSIZE*1 ) {
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wq0 = wp0 = get_unaligned_native(&dptr[z0][d+0*NSIZE]);
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for ( z = z0-1 ; z >= 0 ; z-- ) {
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wd0 = get_unaligned_native(&dptr[z][d+0*NSIZE]);
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wp0 ^= wd0;
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w20 = MASK(wq0);
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w10 = SHLBYTE(wq0);
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w20 &= NBYTES(0x1d);
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w10 ^= w20;
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wq0 = w10 ^ wd0;
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}
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put_unaligned_native(wp0, &p[d+NSIZE*0]);
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put_unaligned_native(wq0, &q[d+NSIZE*0]);
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}
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}
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